The Pattern Almanac 2000

This invention pertains to an air-actuated vibrator of the turbine-type in which the rotor and enclosing chamber is contoured so as to provide within the normal operating range a low noise level which is below 80 db (hertz). In association with this chamber is a novel muffler which receives the output from the chamber and reduces the noise level to about 65 db or less which is much below the tolerance level established as acceptable. The rotor is the only moving part in this vibrator and has its periphery formed with small tooth-like transverse serrations but other similar profiles may be used. The tooth profile is of such small size that the driven rotor which is peripherally driven by pressurized air within a normal supply range produces noise levels which are sufficiently low so that the operation of the vibrator in combination with the associated muffler is considered to be virtually silent.